Gilvocarcin derivatives are coumarin-containing drugs which are currently being tested as candidates for photosensitized UVA treatment of several illnesses. Although vinyl-containing gilvocarcins and furocoumarins both bind covalently to DNA upon UVA irradiation, the latter also show singlet oxygen and superoxide generation as well as photoperoxidation and photobinding of lipids. In this work, the detection and quantification of these photochemical pathways, excluding photocycloaddition to DNA bases, will be examined. Quantum yields for the processes will be determined. Since the methyl-substituted gilvocarcin is not photocytotoxic it will be used as a control in establishing which of these pathways may be important in the gilvocarcin mediated photocytotoxicity. One undergraduate student will participate in this research project to encourage him/her to proceed in graduate studies in a biomedical related area.